Breaker point assembly



Feb. 25, 1947.

Filed July 14, 1943 mnq lmm ungnmil Patented Feb. 25, 1947 UNITED STATES PATENT OFFICE BREAKER POINT ASSEMBLY Orrin H. Thomas, Williamsport, Pa. Application July 14, 1943, Serial No. 494,745

1 Claim. 1

This invention relates to electrical contact points, especially applicable to ignition systems of internal combustion engines and it consists in the constructions, arrangements and combinations herein described and claimed.

In the present day construction of breaker points, there is a decided source of motor inefficiency, and in later stages, complete motor failure which is due, in most cases, to the burning away of the one contact, resulting in a pit being burned in one and a lump formation built up on the other. This resuits in the contact surfaces being reduced to a surface that is insufficient to transfer a current possessing the electrical energy required to produce a spark that will properly ignite and burn the combustible mixture in the engine cylinder, and thus give cause for motor inefficiency and motor failure. Since the electrical energy sent out is dependent upon the current broken in the primary circuit, it is important to keep the current value as high as possible, and therefore necessary to maintain as much contact surface as possible, for in motor operation the contacts are engaged with each other for as little as .004 second each time they close and at speeds above sixty miles per hour even less. If there is insuflicient contact surface at the contacts, when they open and break the primary current the amount of decay of flux in the magnetic circuit of the ignition coil is inadequate to produce the proper tension current in the secondary coil and a, .reak spark which is ineiieotive to the proper ignition of the combustible mixture occurs.

It is therefore an important object of the invention. to provide a novel construction of mounting for one of the contacts whereby a sliding or Wiping action is inherent between the breaker points. thus reducing to a minimum the formation of a pit in one contact and the build-up of a lump on the other, which consequently reduces the failure of adequate current transmission between the contacts.

More specifically it is an object of the invention to provide a novel spring structure which be readily mounted of a breaker assembly, the spring having a contact cooperable with the contact of a fixed arm of the breaker assembly, in a manner to produce a sliding or wiping action between the two contact faces.

Additional objects, advantages and features of invention will be apparent from the following description considered in conjunction with the accompanying drawings, wherein Figure 1 is a top plan view of a distributor,

upon the movable arm partly in section, showing my invention installed therein.

Figure 2 is a vertical section therethrough.

Figure 3 is an enlarged sectional view through the movable breaker arm.

Figure 4 is a fragmentary elevation of a distributor having a modified form of contact arm.

Figure 5 is a perspective view of the contact arm and base mounting in separated relation.

Figure 6 is a perspective view of a further form of contact arm.

There is illustrated a distributor generally indicated by the reference character It] having an assembly plate Ii for mounting of an adjustable contact arm I2 and a cam actuated swinging arm 3. The arm I3 is spring actuated as at M, for holding the rubbing block into engagement with a cam F5.

The arm i2 is provided with a breaker point I 6, the contact face of which is inclined or tapered in a direction opposite that of the contact so that the faces of the contacts may assume a contacting engagement when in closed position.

As shown in Figures 1, 2 and 3, the arm 13 is of the conventional rigid construction and has mounted thereon a rubbing block I3 by means of bolt 2'! and nut 28, the block functioning in conjunction with the cam 15 to separate the breaker points [6 and H, as is well understood.

Upon the free end of the arm I3 there is mounted by means of a screw or other fastener 19, a, spring 20. The spring 20 is substantially U-shaped, presenting a pair of divergent legs 2| and 22, the former being provided with an opening for reception of the fastener I9, while the latter has mounted thereon the contact l1, so positioned as to align with the contact I6.

In use, it will be seen that when the cam i5 is rotated the arm it will be moved outwardly against the action of the spring l4, so as to separate the breaker points I6 and 17, but upon closing movement of the breaker points a flexing of the leg 22 will occur at the time of contacting engagement with the breaker point l5, thereby causing a wiping or sliding engagement between the contact faces, thus reducing the formation of pits or lumps.

It will be noted that due to the tension of the spring M, the contact I! is forcibly engaged with the contact 1 5 so that the leg 22 is given a definite flexing, with consequent sliding action of the contact I! across the contact l6.

In Figures 4 and 5 a modified form is' illustrated, in which the swinging arm I3 is of a combined rigid and flexible nature. The arm i3 is of much shorter length and is apertured as at 23, and further has parallel side walls 26 between which a fiat leaf spring 25 is interposed. The spring 25 has an elongated aperture 26 and through these apertures a bolt 21 is extended and receives a nut 28 for securement of the parts. The free end of the spring 25 has mounted thereon a spring 20' as in the first instance, and the operation is the same, except by the employment of the leaf spring 25, a greater flexibility is obtained, reducing shock between the contact faces as well as increasing the sliding or wiping action between the faces of the breaker points. In addition, by the provision of the elongated aperture 26, adjustment of the arm 25 with respect to the fixed contact it is readily possible. This construction also permits ready replacement of the spring and contact when found necessary.

A modified form of spring arm 25 is shown in Figure 6. In this instance, the arm 25' is bent backwardly upon its length to form a U-shaped spring 20' uponwhich the breaker contact 11' is mounted.

While I have shown and specifically described my invention, this is by the Way of illustration only, and I consider as my own all such modifications in construction as fairly fall within the scope of the appended claim.

I claim:

An ignition timer for internal combustion en- 30 Number 4 gines comprising a fixed arm and a rigid springpressed swinging arm, said swinging arm having a pair of parallel side walls, and an aperture medially thereof, a fiat leaf spring interposed between said walls, said spring having an elongated aperture aligned with the aperture of the arm, means extended through said apertures for adjustably securing said spring, a spring member having a pair of leg members, one of said leg members being fixed to the free end of the flat leaf spring, the other of said leg members extending inwardly longitudinally of the flat leaf sp g and being divergent therefrom, a contact on said last named leg member, a contact on the fixed arm complemental to the first named contact, and means for intermittently moving the swinging arm and flat leaf spring and associated contact into and out of engagement with the contact of the fixed arm, said last named leg member having a fiexure providing a sliding engagement between contacts of the fixed arms and the contact on the divergent leg member.

ORRIN n. THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 2,320,942 Logan June 1, 1943 

